Sea urchin histone genes will be mapped with restriction endonucleases, purified histone mRNAs, homologous RNA polymerases and DNA sequencing techniques in order to elucidate the mechanisms of regulation of these specific protein coding genes. BIBLIOGRAPHIC REFERENCES: Grunstein, M., Schedl, P. and Kedes, L.H.: Sequence analysis and evolution of sea urchin histone H4 (f2a1) messenger RNAs. J. Mol. Biol. 104:351-359, 1976. Holmes, D.S., Cohn, R.H., Kedes, L.H. and Davidson, N.: The positions of sea urchin (S. purpuratus) histone genes relative to restriction endonuclease sites on the chimeric plasmids pSp2 and pSp17. Biochemistry, in press, 1977.